In integer 2's complement arithmetic, every representable bit pattern has a numeric value. In the proposed IEEE standard relating to floating-point (real) number system formats, several types of values are defined:
1. Normalized numbers PA1 2. Zero PA1 3. Infinity PA1 4. Denormalized numbers PA1 5. Not numbers (NaNs)
For purposes of this description, denormalized numbers may be treated the same as very tiny normalized numbers.
The currently proposed standard for floating point numbers proposed by the IEEE requires, among other things, that "It shall be possible to compare floating point numbers in all supported formats even if the operands' formats differ . . . Four mutually exclusive relations are possible: `less than`, `equal`, `greater than`, and `unordered`. The last case arises when at least one operand is NaN. Every NaN shall compare `unordered` with everything, including itself. Comparisons shall ignore the sign of zero (so+0=-0)."
In known floating point condition code generation systems, the above relations are generated directly, through the use of complex logic, from the magnitude relationships between the two operands. This requires extensive logical operation and circuitry.